1. Field of the Invention
The present invention relates to an adjustment device for a compound miter saw, and more particularly to an adjustment device to efficiently position the compound miter saw to cut an angle in a workpiece.
2. Description of Related Art
Compound miter saws are used to cut a piece of metal, wood or other material at a precise angle. Many applications require that a piece have an angled end, called a chamfer. Compound miter saws today have an adjustment device to adjust the saws to cut a piece at a specific angle.
With reference to FIG. 7, a conventional adjustment device (not numbered) for a compound miter saw (not shown) comprises a base (60), and a turning disk (63). The base (60) has a spring (61) and ball (62) combination, a top (not numbered), a center (not numbered), a central opening (not numbered) and a spring-ball hole (not numbered). The central opening is defined through the top at the center of the base (60). The spring-ball hole is defined in the top of the base (60) adjacent to the central opening.
The turning disk (63) is rotatably mounted in the central opening on the top of the base (60). The turning disk (63) has a top (not numbered), a bottom (not numbered), an annular lip (not numbered) and detents (64). The top of the turning disk (63) is adapted to support a piece (not shown) to be cut where a cutting mechanism (not shown) cuts the piece. The annular lip is formed at the bottom of the turning disk (63) and corresponds to the central opening in the base (60). The annular lip is rotatably held in the central opening in the base (60) so the turning disk (63) will rotate on the base (60).
The detents (64) are V-shaped and are formed on the bottom of the turning disk (63) corresponding to the spring-ball hole in the base (60). The spring (61) and the ball (62) are mounted in the spring-ball hole in the base (60) so the ball (62) partially extends from the spring-ball hole to selectively engage one of the detents (64).
The turning disk (63) is rotatably attached to the top of the base (60), and the bottom of the turning disk (63) presses against the ball (62) and compresses the spring (61) in the spring-ball hole. The compression of the spring (61) will create a restitution force that pushes the ball (62) upward to engage one of the detents (64) to hold the turning disk (63) in place.
However, the conventional adjustment device for a compound miter saw that uses the restitution force of the spring (61) to push the ball (62) into a detent (64) may easily slip from the desired position. When the turning disk (63) is subjected to an inadvertent impact, the spring (61) may be compressed and the ball (62) may slip from the V-shaped detent (64) that allows the turning disk (63) to rotate. So, the turning disk (63) cannot be efficiently locked and precisely held at all times.
Although the adjustment device has been modified to increase the restitution force of the spring (61) to improve the connection between the ball (62) and the detents (64), the increased restitution force of the spring (61) will cause rotating the turning disk (63) more difficult. The modified adjustment device is inconvenient to operate.
To overcome the shortcomings, the present invention provides an adjustment device for a compound miter saw to mitigate or obviate the aforementioned problems.
The main objective of the invention is to provide the ability to precisely position and firmly hold a miter saw turntable so the compound miter saw can cut a precise, desired angle.
Another objective of the invention is to provide the ability to lock the turntable of the miter saw after the turntable has been adjusted to a desired position.
Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.